1. Technical Field
The invention relates to an image generating apparatus, an image generating method, an image generating program, a computer readable medium storing the image generating program and a computer data signal embedded with the image generating program.
2. Related Art
Prior to printing a document requested by a customer, there is a case where a comprehensive layout is provided to the customer as a sketch showing an outline of a design. In many cases, such a comprehensive layout is output with a color printer rather than a printing machine that actually prints the document.
However, whereas the printing machine can provide a semi-transparent effect by overlapping inks, if objects to be drawn are overlapped in an output process of the color printer, a color of an object on a background color is replaced with a color having a higher overlapping priority (a color to be drawn on a more foreground side), and an effect by overlapping inks cannot be achieved in many cases.
That is, consider two colored disks as conceptually shown in FIG. 5. It is assumed that a first disk A is drawn on a more background side and that a color of the first disk A is set to cyan (C): 100%, magenta (M): 0%, yellow (Y): 10%, black (K): 0%. Also, it is assumed that a second disk B is drawn on a more foreground side with partially overlapping the first disk A and that a color of the second disk B is set to cyan (C): 0%, magenta (M): 0%, yellow (Y): 100%, black (K): 10%. In this case, a color in a portion where the first disk A and the second disk B overlap becomes the color of the second disk B drawn on the more foreground side (C: 0%, M: 0%, Y: 100%, K: 10%) and the colors of cyan (C) and magenta (M) on the background side are not reflected (so called “knockout”).
Hence, a process of not replacing a color of an object on a background side with a color, of a plate, set to 0% when colors are divided into respective plate (“nonZero Overprint” in, for example, the postscript (registered trademark)) has been proposed. According to this process, in the above-described case, as shown in FIG. 6, in the portion where the first disk A and the second disk B overlap, a color component of the second disk B drawn on the more foreground side having a value of 0% is set to a value of the color component of the first disk A on the more background side. That is, the color of that portion is set to C: 100%, M: 0%, Y: 100%, K: 10%, and the colors of cyan (C) and magenta (M) on the background side are reflected. Thus, an effect by overlapping inks can be achieved virtually.
That is, in the nonzero overprint, if there is an object in which, for example, although colors are put on plates of yellow and black, colors are not put on plates of cyan and magenta (that is, the plates of cyan and magenta are designated to have 0%) in forming of a bitmap image, the color of the background is not masked by the plates of cyan and magenta set to 0%.